Thilthorpe's initial prognosis is a jarred left knee, suffered in the final quarter of Adelaide's 17.15 (117) to 7.8 (50) triumph at Richmond Oval on Saturday.
"I'm not an expert, but the doctors are hopeful that it's nothing major," Nicks said.
"We will have to wait another 24 hours just to confirm that."
Thilthorpe landed awkwardly in a marking contest, then sat on the ground for a period of time before hobbling off, assisted by a medico.
Adelaide's Riley Thilthorpe (right) injured his knee during the Crows' win over West Coast. (Matt Turner/AAP PHOTOS)
"Sometimes your heart is in your mouth. Today was one of those moments," Nicks said.
"But we have got a squad of players too. Riley is really important to what we're doing and he's a great player, but we've got others.
"And that's part of pre-season. We train on the rivet, we go hard.
"That's how we've trained right throughout, so we've been pushing the envelope, let alone playing games like this.
"And we'll continue to do that. That's how we work, that's how we believe we play our best footy."
Adelaide livewire Izak Rankine kicked four goals, the West Adelaide product relishing a return to his state league home ground for the trial game.
Rankine also directly set up two goals for teammates and collected 18 disposals in a dual forward-midfeld role.
"Just that little bit more time around the ball for him, I think it has really rewarded him and our team," Nicks said.
"He's unique in the way he plays footy, there's things he does that a lot of us can't, so we've really enjoyed giving him that freedom."
Rankine's fellow small forward Josh Rachele slotted three majors and Reilly O'Brien produced a ruck masterclass with 34 hit-outs, eight clearances and 22 disposals.
O'Brien gave silver service to his midfielders, with Matt Crouch (23 touches), captain Jordan Dawson (28), Rory Laid (26) and on-ball pinch-hitters Rankine and Sam Berry (22, two goals) all thriving.
West Coast's prime mover Tim Kelly (26 possessions, one goal) was prominent and the Eagles' prized No.1 draftee Harley Reid (20 disposals, five clearances) showed glimpses of class.
"His second game in, he's been playing a bit of midfield and a bit of playing behind the ball at half-back," Eagles assistant coach Jarrad Schofield said of Reid.
"And he spent some time down deep in our forward line.
"He grew into the game again.
"We know that he's a bit of a bull when he gets going in the contest, and he showed obviously his talents once again.
"He's learning a new system within our structure and we thought he performed really well."
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